OK, I tried to get the ball rolling on a discussion of the biggest question I was left with from the film, but you all seem to be fixated on accusing me of genocidal thoughts, so I'm just going to skip to the part where I give my thoughts on the subject.
Here's what we're given at the end of the movie:
1. Hela is too strong.
2. She draws her power from Asgard.
3. We must unleash Surtur to destroy Asgard and deprive Hela of her power source.
That's the plan. It's pretty straightforward.
BUT, earlier in the movie were are told:
Thor also draws his power from Asgard.
Logic tells us that if you destroy Asgard, this will also affect Thor.
The movie does not give us information on Thor's status in this regard. After the destruction of Asgard, he isn't seen doing anything more strenuous than having a conversation and sitting in a chair.
So, what possibilities are there?
First Theory: Asgard is the people. In which case Thor is unaffected by the destruction of the physical location of Asgard and retains his previously shown power levels. Some considerations for this theory:
1. Hela would likewise be unaffected, since the place was destroyed and not the people.
2. This raises the question of how Hela draws power from the people of Asgard, vs. the place being imbued with power.
a. She's a Death goddess, but she only shows control over the dead when using the Eternal Flame. So, drawing power from Asgard's dead probably isn't a viable explanation.
b. She's not a very positive death goddess. She's not someone who ushers old dogs over the Rainbow Bridge. If anything, she's the scary side of Death, the grim reaper, etc. So, plausible that she draws power from Asgard through feeding on the fear of Asgardians.
i. Odin seems to have raised Thor to be the counterbalance to Hela, so it would jibe that he draws power by inspiring hope and positive feelings in the Asgardian people.
So, the "Asgard is the people" theory could work. It makes blowing up the place Asgard more of a delaying tactic, and raises the question of why Hela is so strong before even getting to Asgard.
Second Theory: Odin didn't tell the whole story. Perhaps the floating land of Asgard is a repository for the Odinforce, and breaking it deprives Hela access, but Thor doesn't need the rock to access the Odinforce. Low probability of anything Odinforce involved in the MCU, IMO. They haven't mentioned it up until now and it doesn't seem like the sort of thing they want to get into.
Third Theory: Thor did get depowered, and is now operating at the same level as any other elite Asgardian warrior -- which is still pretty impressive. Perhaps he goes into retirement from the superhero life to rule Asgard and later decides to make a new hammer and empower the next generation of Thor? Possible.
I personally think they're going to go something to do with "Asgard is the people," mainly because that's the only thing they gave us in the movie. Second one is "Odin didn't tell Thor everything," because it's a recurring theme.